The present invention relates to a cosmetic composition comprising .gamma.-L-glutamyl-L-cystine, .gamma.-L-glutamyl-L-cysteine disulfide, oxidized glutathione or a derivative thereof, the amino group of which is acylated with an alkanoyl group or an aroyl group.
Cosmetics have hitherto been developed for the purpose of preventing blackening of the skin caused by sunburn/suntan or for the prevention or treatment for pigmentation such as stains of freckles.
Glutathione (.gamma.-L-glutamyl-L-cysteinyl-glycine) is inherently present in vivo. It is known to formulate glutathione in cosmetics or external remedies.
Various formulations of glutathione derivatives in cosmetics have also been known (Japanese Published Examined Patent Application Nos. 1505/73 and 29139/73, WO 86/05783, Ger. offen. 2245903).
With respect to oxidized glutathione, a hair modifying composition comprising the same compound and the like are known (Japanese Published Unexamined Patent Application No. 188618/88, U.S. Pat. No. 4,812,307, European Patent Application No. 299,764).
It is also known to formulate kojic acid or arbutin in cosmetics (Japanese Published Examined Patent Application No. 18569/81 and Japanese Published Unexamined Patent Application No. 16906/85). But kojic acid and arbutin are unstable and slightly soluble in water and they can not effectively prevent blackening of the skin caused by sunburn/suntan.
Further, it is difficult to formulate glutathione in cosmetics because of its unstableness and offensive odor.
It has been desired to develop whitening cosmetics which are stable to heat and light, free of toxicity and skin damages, and can be used safely.